

INTRODUCTION. 



IN this treatise the principles of electricity are 

 presented untrammeled, as far as possible, by mathe- 

 matical formulae, so as to meet the requirements of a 

 large class who have not the time or opportunity to 

 master the intricacies of formulae, which are usually so 

 perplexing to all but expert mathematicians. 



This class includes those whose knowledge of 

 electricity is limited to .the practical details of teleg- 

 raphy, telephony, and electric lighting; also those 

 among the liberally educated, who desire to review 

 electric science in the light of recent investigation; 

 and those who wish to study its elementary principles, 

 preparatory to a more extended course, which shall 

 embrace all the details of electric measurement arid 

 electric engineering. 



The original plan included dynamic as well as static 

 electricity, embracing its practical application to the 

 arts ; but it was subsequently thought best to confine 

 the present work to static electricity alone, to meet 

 the wants of those who are less familiar with its prin- 

 ciples than with those of dynamic electricity, and to 



